Mercury switch mounting



Aug. 25,1953 L. H. MCCAMMANT I 2,650,274

MERCURY SWITCH MOUNTING Filed July 18, 1951 Patented Aug. 25, 1953 T.MERCURY SWITCH MOUNTING I Leonard 11. McCammant, Rockford, Ill.,assignor '1; to. iGBQL-JD; RopenaCorporation, Rockford, 3111., v. acorporation ofEIllinois Application July; 18, 1951,.Seriall No. 237,413

-:4.-Claims. 1 (Cl. 20061.47)

"This inventionrelates to amounting-for I an electricalswitch; andimparticular to amountin'g f or a mercury switch associated witlr themain "shutwfi -valvefor a-top burner on a gas stove.

"An object of this invention -isto provide a novel-mounting for amercury switch' opera'tive to tilt the-same to -close-the'electricci-rouit-therethrough in' response 'to angular movement'of arotary shaft.

Another objectof-this-invention is to'asso- 'ciate a-mercury-switch witha'iuelvalvein a novel manner so that the mercury switch is tilted toclose-an electrical circuit in -response'to opening of the-ruelvalve-andthe mercury switch remains in the closed condition mall-open positionsof the-fuel valve.

"Another-object of this invention is to tilt a mercury switch to providea closed electrically conductive path therethrough in response toopening of a fuel valveand-to maintain the switch in the same tiltedposition at all open positions-of the fuel valve.

' A further-object of this invention is to provide a mercury switch inassociation-with a'fuel valve actuated by a -rotary-'stem-, wherein-themercury switch is maintained closed in all-open positions of the fuelvalve even when the-rotary valve stem rotates-more than 180-degrees in"moving the valve from its closed position to its full open position.

' A still further object of this-invention is to limit-the angularti-lting of amercury switch in response to theopening of a valve so asto minimize the displacement of the external electrical conductorsconnected to-the switch electrodes.

Other and further objects and ad-vantages'of the invention willlee-apparent from the-following description of a-preferred form'thereof.

' Inth'edrawings:

' Figure -1 is aperspective 'viewillustrating-the switch mountingassociated with the manuallyoperated main shut -ofi valve controllin thesup- '-ply orgas to --a top burner on-a gas stove.

Fig. 2 is an end view of theswltch mounting and the valve stem in theclosed" position of' the valve-;-and Fig. 3 is an endview'of the-switchmounting and the valve-stem when the valvestem is rotatedto openthe-valve.

' For purposes of-illustrating the principles of the present invention,the following-description is directed toward-its -use "inconnection'with a manually-operated main shut -ofi valve controlling thesupply of gas to a top-burner-on a gas stove.- However, otherapplications will "suggest all . the other switch electrode.-

themselves to those skilled in the art,--and it is not intended thatthefollowing description be construedaslimiting the invention tothe-particular described use.

As is conventiona-l in the gas stove art, a main shut-off valve l ismounted above a manifold 2 and communicates therewith tosupply gas tothe top burner 3 of a gas stove; Openin and closing of the valve iseffected through-a rotary valve stem-4 operated by a manual knob 5.Beyond the casing-ofthevalve the stem is formed as the majorsegment of acylindrical tube to provide an outer periphery of the stem which formsthe major segment of a-circle-,"with the center of the circlebeing-located at the longitudinal rotational axis of the stem-and fiatsurfaces 6, l at the cut away portion of the stem spaced more thandegrees apart round the circumferenceof the stem.

At the rear of -the valve casing a back plate 8 is mounted in fixedrelation thereto. Ascrew 9 zconnected'to' back plate B -and extendingoutwardly therefrom provides a pivotal axis for a bracket, generallyindicated at l0, The pivotal 'axis 9 of the'bracket is-spaced -from thelongitudinal rotationalaxis ofvalve-stem 4.

At its lower endbracket 10 is iormed'with an :1ntegral loop-|-:lwhich-carries a mercury switch l2- oi-conventional design. Commonlymercury switches are either of the type having a pair of spacedelectrodes and a pool of mercury within the casing of the switch orof-thetype in which a single electrodeand-themercury pool are within theswitch casin and the casing-itself forms In both types, when the switchcasing is tilted to a'desired-angular vposition the mercury pool bridgesthe space betweennthe. switch electrodes to form an electricallyconductive path throughthe switch. When theswitch is in, its normalposition the mercury epool .is ,out oficontact with-one orbothof ;the

switch electrodes. andtheswitch is open.

Theswitch-bracket U} is alsoi formed with a hat transverselyextendingarm I3 which bears against the lowerrside Of .the valve-stem 4. A leafspr n I4, is secured to a transverse arm I5 of .the switch bracket and'has its free .end biased to engage the, top of thevalv stem tocontinually urge the bracket arm 13 into engagemen't with the adjacentlower peripheral portion of the valve stem.

the normal position of the valve stem 4 the-valve is closed, switchbracket arm [3 engages thefiat faces {Sand on the valve stem, and theswitchbracket ispositioned angularly to hold the mercury switch If! inits open condition.

To open the valve the stem i is rotated in a counterclockwise directionin the drawing. The flat surfaces 6, l on the valve stem move away fromengagement with the adjacent bracket arm l3, and the circular peripheralportion of the valve stem rides over the top face of the bracket arm I3.Since this circular peripheral portion on the valve stem at its point ofengagement with bracket arm I3 is spaced farther below the longitudinalaxis of the valve stem than were the flats 6, T when they engaged thebracket arm 13, the bracket arm 13 is displaced downwardly by thisangular movement of the valve stem. The entire switch bracket is therebydisplaced angularly in a clockwise direction about its pivotal axis 9 totilt the casing of the mercury switch to its closed position.

Continued rotary movement of the valve stem 4 to fully open the valvemerely maintains the mercury switch in its same angular position becausethe entire circular periphery of the valve stem, which progressivelyrides over the bracket arm l3 during such continued opening movement ofthe Valve, is concentric with the longitudinal rotational axis of thevalve stem. Because of this, the mercury switch remains closed eventhough full opening movement of the valve stem may involve more than 180degrees rotation thereof. This is a distinct advantage over prior artconstructions in which the mercury switch bracket was mounted directlyon the valve stem and a rotary movement of the valve stem of more than180 degrees resulted in tilting the mercury switch to a position wherethe electrical circuit through it was broken. With the presentconstruction, the mercury switch remains closed independent of theamount of angular rotation of the valve stem which is required to fullyopen the valve.

In addition, the limited tilting of the mercury switch in the presentinvention results in a minimum displacement of the conductors It whichconnect the switch electrodes to the rest of the electrical circuit.These conductors are not wrapped around the valve stem as the latter isrotated toward the full open position of the valve, as is the case inthe prior art constructions where the mercury switch moved in unisonwith the valv stem throughout the full angular movement thereof. Thelead in conductors Hi can therefore be made shorter in length and theliability of breaking these conductors because of a relatively largetravel of the mercury switch is obviated.

To close the valve the valve stem 4 is rotated in the opposite direction(clockwise in the drawing) about its longitudinal axis. When the flats 6and I on the valve stem have been returned to their normal horizontalposition the leaf spring [4 insures that the mercury switch bracket l0returns to its normal position with the arm [3 engaging the flats 6 and1 on the stem. The mercury switch is thus returned to its normalposition to break the circuit through the switch.

While there has been described a specific preferred form of the presentinvention, it is to be understood that various modifications andvariations of the illustrated device may be resorted to withoutdeparting from the spirit and scope of the invention. For example, themercury switch may be of a design which requires a reater tilting inorder to close than would be effected by engagement of its mountingbracket directly with the periphery of the valve stem. Obviously acollar having a shape similar to the described valve stem shape, but oflarger circumference, could be attached to the valve stem to move inunison therewith and to engage the switch bracket for tilting it thedesired amount.

I claim:

1. In a switch mounting, in combination, a rotary valve stem controllingthe opening and closing of a valve, said stem being provided with acircular peripheral portion and a peripheral portion cut away to providea fiat surface spaced closer to the longitudinal axis of the stem thansaid circular peripheral portion provided therewith, a bracket pivotallymounted about an axis spaced from the longitudinal axis of the stem, aleaf spring mounted at one end on the bracket and at a free portionremote from its mounted end engaging the stem to urge a surface on thebracket into continuous engagement with the adjacent surface of theperipheral portion provided with the stem, whereby the rotary positionof the stem determines the angular position of the bracket about itspivotal axis, and switch means carried on the bracket operable toprovide one circuit condition when said bracket surface engages the flatperipheral portion provided with the stem to position the switch meansin one position and operable to provide a different circuit conditionwhen said bracket surface engages the circular peripheral portionprovided with the stem'to tilt the switch means to another positionspaced farther from the longitudinal axis of the stem.

2. In a switch mounting, in combination, a rotary valve stem controllingthe opening and closing of a fuel valve, said stem carrying a circularperipheral portion and a peripheral portion cut away to provide a flatsurface spaced closer to the longitudinal rotational axis of the stemthan said circular peripheral portion provided therewith, a bracketpivotally mounted about an axis spaced from the longitudinal rotationalaxis of the stem and extending parallel thereto, a leaf spring attachedat one end to the bracket and at a free portion remote from its mountedend bearing against the stem to urge a surface on the bracket intocontinuous engagement with the adjacent surface of the peripheralportion carried on the stem, whereby the rotary position of the stemdetermines the angular position of the bracket about its pivotal axis,and a mercury switch carried on the bracket to move angularly in unisontherewith operable to provide one electrical condition when said bracketengages the flat peripheral surface portion carried on the stem toposition the mercury switch in one position and operable to provide adifferent electrical condition when the stem is rotated to position saidcircular peripheral portion carried on the stem in engagement with saidbracket surface to tilt the mercury switch to a different position.

I 3. In a switch mounting, in combination, a valve for controlling theflow of gas to.a burner, a rotary valve stem controlling the opening andvclosingof said valve, said stem projecting beyond one end of the valveand provided thereat with a circular peripheral portion and a peripheralon said one end of the valve about an axis spaced from the longitudinalaxis of the stem and extending parallel thereto, a leaf spring attachedat one end to the bracket and remote from its mounted end bearingagainst the upper peripheral portion provided with the stem to urge asurface on the bracket into continuous engagement with the lowerperipheral portion provided with the stem, whereby the rotary positionof the stem determines which particular peripheral portion providedtherewith is in engagement with said surface on the bracket to therebydetermine the angular position of the bracket about its pivotal axis,and a mercury switch carried on the bracket to move angularly in unisontherewith operable to provide an open circuit when said fiat surface onthe bracket engages the peripheral portion provided with the stem toposition the mercury switch in one angular position and operable toprovide a closed circuit when the stem is rotated to position itsassociated circular peripheral portion in engagement with said surfaceon the bracket to tilt the mercury switch to a difierent angularposition.

4. For use in a burner ignition system for gas stoves, the combinationof a valve arranged to control the flow of gas to a burner, a rotaryvalve stem controlling the opening and closing of the valve, said valvestem projecting beyond one end of the valve and being provided thereatwith a circular peripheral portion and a peripheral portion cut away toprovide a flat surface spaced closer to the longitudinal axis of thestem than said circular peripheral portion, a bracket pivotally mountedon said one end of the valve about an axis extending parallel to thelongitudinal axis of said stem in spaced relation therefrom, saidbracket being provided with a first arm extending away from said one endof 6 the valve above the pivotal axis of the bracket, an elongated leafspring mounted on said first arm of the bracket engaging the upper sideof the peripheral portion provided with the stem, said bracket beingprovided with a second arm extending away from said one end of the valveand positioned to engage the lower side of the peripheral portionprovided with the stem, said spring acting between the peripheralportion provided with the stem and the bracket to bias the bracket toposition said second arm in engagement with the lower side of theperipheral portion provided with the stem, said stem in the closedposition of the valve positioning said fiat peripheral portion at itslower side to engage said second arm on the bracket and said stem whenturned to open the valve positioning said circular peripheral portion atits lower side to engage said second arm on the bracket, whereby therotary position of the stem determines the angular position of thebracket about its pivotal axis, and a mercury switch carried by thebracket positioned to open a circuit through the switch when said flatperipheral portion provided with the stem engages said second arm on thebracket, said mercury switch being positioned to close a circuit throughthe switch when said circular peripheral portion provided with the stemengages said second arm on the bracket.

LEONARD H. MCCAMMANT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,566,549 McMeen Dec. 22, 1925 1,933,062 Keebler et al. Oct.31, 1933 2,099,417 Bast Nov. 16, 1937 2,399,033 Hudson Apr. 23, 1946

